Release 0.32.0

Improvements

• Refactor LKokkos Measurements class to use (fast) specialized functors whenever possible. (#481)

• Merge Lightning Qubit and Lightning Kokkos backends in the new repository. (#472)

New features since last release

• The lightning_kokkos backend supports Nvidia GPU execution (with Kokkos v4 and CUDA v12). (#477)

• Complete overhaul of repository structure to facilitate integration of multiple backends. Refactoring efforts we directed to improve development performance, and code reuse and decrease overall overhead to propagate changes through backends. The new C++ modular build strategy allows faster test builds restricted to a module. Update CI/CD actions concurrency strategy. Change the minimal Python version to 3.9. (#472)

• Wheels are built with native support for sparse Hamiltonians. (#470)

• Add native support to sparse Hamiltonians in the absence of Kokkos & Kokkos-kernels. (#465)

Breaking changes

• Rename QubitStateVector to StatePrep in the LightningQubit and LightningKokkos classes. (#486)

• Modify adjointJacobian methods to accept a (maybe unused) reference StateVectorT, allowing device-backed simulators to directly access state vector data for adjoint differentiation instead of copying it back-and-forth into JacobianData (host memory). (#477)

Documentation

• Integrated new unified docs for Lightning Kokkos and Lightning Qubit packages. (#473)

Bug fixes

• Ensure PennyLane has an active_return attribute before calling it. (#483)

• Do no import sqrt2_v from <numbers> in Util.hpp to resolve issue with Lightning-GPU builds. (#479)

• Update the CMake internal references to enable sub-project compilation with affecting the parent package. (#478)

• apply no longer mutates the inputted list of operations. (#474)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Christina Lee, Vincent Michaud-Rioux, Lee J. O'Riordan